Cleanup some more llpvm_changes flags

I was doing another change in vm tool codebase, and the `llpvm_changes`
flag was bugging me, hence this patch :)

Bug: 365767108
Test: m
Change-Id: I8172514617f400c01c73d9a107d4db15430cbce5
diff --git a/android/vm/src/run.rs b/android/vm/src/run.rs
index a362b8e..4ddde9d 100644
--- a/android/vm/src/run.rs
+++ b/android/vm/src/run.rs
@@ -86,8 +86,8 @@
         )?;
     }
 
-    let instance_id = if cfg!(llpvm_changes) {
-        let id_file = config.instance_id()?;
+    let instance_id = {
+        let id_file = config.instance_id;
         if id_file.exists() {
             let mut id = [0u8; 64];
             let mut instance_id_file = File::open(id_file)?;
@@ -99,9 +99,6 @@
             instance_id_file.write_all(&id)?;
             id
         }
-    } else {
-        // if llpvm feature flag is disabled, instance_id is not used.
-        [0u8; 64]
     };
 
     let storage = if let Some(ref path) = config.microdroid.storage {
@@ -251,10 +248,8 @@
         ..Default::default()
     };
 
-    if cfg!(llpvm_changes) {
-        app_config.set_instance_id(work_dir.join("instance_id"))?;
-        println!("instance_id file path: {}", app_config.instance_id()?.display());
-    }
+    app_config.set_instance_id(work_dir.join("instance_id"));
+    println!("instance_id file path: {}", app_config.instance_id.display());
 
     command_run_app(app_config)
 }